card_busy is only used/tested on SDHI for R-Car Gen2 and later.
Move it to the SDHI driver, so we can then activate it conditionally
depending on the SDHI type.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>